Stent

ABSTRACT

A stent comprising a stent body and a plurality of cells is disclosed. Each cell includes two structural members extending in an undulating pattern. Each structural member includes a plurality of cell segments defining a plurality of peaks and valleys therebetween. A first segment and a second segment defining a first peak, the second segment and a third segment defining a first valley, the third segment and a fourth segment defining a second peak, the fourth segment and a fifth segment defining a second valley, the fifth segment and a sixth segment defining a third peak. The first peak, the second peak and the first valley include a first radius of curvature. The third peak and the second valley include a second radius of curvature. The first radius of curvature is larger than the second radius of curvature.

This application is a continuation of U.S. patent application Ser. No.14/878,600, filed Oct. 8, 2015 and naming inventors Vogel et al., whichis a continuation of U.S. patent application Ser. No. 13/834,840, filedMar. 15, 2013 by Vogel et al., now U.S. Pat. No. 9,180,031, the entirecontent of each application is incorporated herein by reference.

BACKGROUND 1. Technical Field

The present disclosure relates generally to stents, and, in particular,relates to stents having nodes with particular radii of curvatures.

2. Description of Related Art

Stents are widely used for numerous applications where the stent isplaced in the lumen of a patient and expanded. Such stents may be usedin coronary or other vasculature, as well as other body lumens.

Commonly, stents are cylindrical members. The stents expand from reduceddiameters to enlarged diameters. Stents may either be self-expanding orballoon-expandable. Self-expanding stents are generally inserted intovasculature via a delivery device; the removal of the delivery devicecauses the stent to radially expand. Balloon-expandable stents areplaced on a balloon catheter with the stent in the reduced-diameterstate. So placed, the stent is advanced on the catheter to a placementsite. At the site, the balloon is inflated to expand the stent to theenlarged diameter. The balloon is deflated and removed, leaving theenlarged diameter stent in place. So used, such stents are used tosubstantially retain or expand diameters of occluded sites within apatient's vasculature or other lumen.

Examples of stents are numerous. For example, U.S. Pat. No. 5,449,373 toPinchasik et al. teaches a stent with at least two rigid segments joinedby a flexible connector. U.S. Pat. No. 5,695,516 to Fischell teaches astent with a cell having a butterfly shape when the stent is in areduced-diameter state. Upon expansion of the stent, the cell assumes ahexagonal shape.

When stents are placed in certain parts of the body, it may be desirablefor the stent to be both strong and flexible. For example, when a stentis placed within a patient's vasculature at or near a patient's joint(e.g., hip, knee, elbow, etc.), the stent may be bent often and may besubject to a relatively large amount of mechanical strain. Thus, a stentthat is both flexible and strong may be desirable for use in these andother instances.

SUMMARY

The present disclosure relates to a stent comprising a stent body and aplurality of cells. Each cell includes two structural members extendingin an undulating pattern. Each structural member includes a plurality ofcell segments defining a plurality of nodes therebetween. The radius ofcurvature of a first node is different from the radius of curvature of asecond node.

In disclosed embodiments, the radius of curvature of the first node isbetween about 200% and about 700% larger than the radius of curvature ofthe second node.

In disclosed embodiments, the radius of curvature of the first node isbetween about 500% and about 600% larger than the radius of curvature ofthe second node.

In disclosed embodiments, the radius of curvature of the first node isabout 250% larger than the radius of curvature of the second node.

In disclosed embodiments, the radius of curvature of the first node isbetween about 0.0030 inches and about 0.0040 inches. Here, it isenvisioned that the radius of curvature of the second node is betweenabout 0.0001 inches and about 0.0010 inches.

In disclosed embodiments, the stent body includes a predeployed insidediameter of between about 0.0500 inches and about 0.0600 inches.

The present disclosure also relates to a stent comprising a stent bodydefining a length and comprising a plurality of cells. Each cellcomprises two structural members extending in an undulating pattern.Each structural member comprises a plurality of cell segments defining aplurality of peaks of valleys therebetween. A first segment and a secondsegment define a first peak. The second segment and a third segmentdefine a first valley. The third segment and a fourth segment define asecond peak. The fourth segment and a fifth segment define a secondvalley. The fifth segment and a sixth segment define a third peak. Thefirst peak and the first valley include a first radius of curvature, andthe second peak, the third peak and the second valley include a secondradius of curvature. The first radius of curvature is larger than thesecond radius of curvature.

In disclosed embodiments, the first radius of curvature is between about200% and about 700% larger than the second radius of curvature.

In disclosed embodiments, the first radius of curvature is between about500% and about 600% larger than the second radius of curvature.

In disclosed embodiments, the first radius of curvature is about 250%larger than the second radius of curvature.

In disclosed embodiments, the first radius of curvature is between about0.0030 inches and about 0.0040 inches. Here, it is disclosed that thesecond curvature is between about 0.0001 inches and about 0.0010 inches.

In disclosed embodiments, each structural member includes a seventhsegment and an eighth segment. The sixth segment and the seventh segmentdefine a third valley. The seventh segment and the eighth segment definea fourth peak. The third valley includes the second radius of curvature,and the fourth peak includes the first radius of curvature. Here, it isdisclosed that the first radius of curvature is between about 200% andabout 700% larger than the second radius of curvature.

In disclosed embodiments, the first radius of curvature is between about0.0030 inches and about 0.0040 inches, and the second radius ofcurvature is between about 0.0001 inches and about 0.0010 inches. Here,it is disclosed that the stent body includes a predeployed insidediameter of between about 0.0500 inches and about 0.0600 inches.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will be readily appreciated byreference to the drawings wherein:

FIG. 1 is a plan view of a stent according to an embodiment of thepresent disclosure as it would appear if it were longitudinally splitand laid out flat;

FIGS. 2 and 3 are enlarged views of portions of the stent of FIG. 1;

FIG. 4 is a plan view of a portion of the stent of FIG. 1 in adeployed/expanded orientation, the stent has been longitudinally cut andlaid flat; and

FIGS. 5 and 6 are enlarged views of portions of the stent shown in FIG.4.

DESCRIPTION

In the following description, the terms “proximal” and “distal” as usedherein refer to a direction or a position along a longitudinal axis of acatheter or medical instrument. The “proximal” or “trailing” end of theinstrument is generally the segment of the instrument that is closest tothe clinician or to the entrance site into a body. The “distal” or“leading” end of the instrument is generally the segment of theinstrument placed farthest into a body lumen from the entrance site.Additionally, the term “preloaded” relates to the configuration of thestent prior to the stent being loaded into a catheter, and the term“predeployed” relates to the configuration of the stent while the stentis compacted into the catheter.

The stent of the present disclosure has particular application in thevasculature of a patient where it is subject to a relatively high amountof strain and movement. For example, the disclosed stent may be suitablefor use within the vasculature of a patient's hip area, e.g., to helpreduce problems associated with a deep vein thrombosis (DVT). However,the disclosed stent may be used in any interventional, diagnostic,and/or therapeutic procedure. The stent may be a component of anapparatus or system used in conjunction with any of the aboveapplications.

The various embodiments of the disclosure will now be described inconnection with the drawings. It should be understood that for purposesof better describing the disclosure, the drawings may not be to scale.Further, some of the figures may include enlarged or distorted portionsfor the purpose of showing features that would not otherwise beapparent.

With initial reference to FIG. 1, the present disclosure includes astent 100. Stent 100 may be expanded from a rest diameter (andcorresponding a rest circumference) to an expanded or enlarged diameter.While stent 100 is generally used when in a cylindrical configuration,for ease of illustration FIG. 1 illustrates a stent 100 in a flattenedcondition. Moreover, FIG. 1 shows stent 100 cut longitudinally along itslength L and laid flat, and is representative of the stent 100 afterstent 100 has been laser cut from a shape-memory tube, for instance, butbefore stent 100 has been shape-set to the expanded diameter. FIG. 4shows a portion of the stent 100 after the stent has been shape-set tothe desired expanded diameter. In both FIGS. 1 and 4, the stent 100extends along elongated axis A-A and includes a stent body (i.e., athree-dimensional structure) having cell defining portions that define aplurality of cells 120, which are bounded areas which are open (i.e.,extend through the wall thickness of the stent 100). After the stent 100has been shape-set to the expanded diameter D as shown in FIG. 4, thecells 120 are generally more open than the cells depicted in FIG. 1.

With continued reference to FIG. 4, cells 120 have a longitudinal ormajor axis X_(M)-X_(M) and a transverse or minor axis X_(m)-X_(m); themajor axis of the cell X_(M)-X_(M) is perpendicular to the longitudinalaxis A-A of stent 100. In disclosed embodiments, cell 120 may berepeated throughout a least a portion of the length L and the diameter Dof the stent 100 (i.e., each cell 120 may be substantially identical toother cells 120).

Referring to FIGS. 2 and 3, which are enlarged portions of the stent 100of FIG. 1, the cell defining portions of stent 100 include firstconnection locations 130 and second connection locations 132. First andsecond connection locations 130, 132 are where circumferentiallyadjacent cell defining structures, as defined relative to axis A-A, areconnected together, and where longitudinally adjacent cell definingportions, as defined relative to the axis A-A, are connected together.

With particular reference to FIG. 4, cells 120 are defined by portionsof the tube material and include first and second longitudinal segments140 a and 140 b, collectively referred to as cell segments 140. Withadditional reference to FIGS. 3 and 6, each of which illustrates half ofa cell 120, each cell segment 140 has an undulating pattern whichdefines a plurality of peaks 150, 152, 154, 156 and valleys 160, 162,164. The peaks 150, 152, 154, 156 are spaced outwardly or away from thelongitudinal axis X_(M)-X_(M), and the valleys 160, 162, 164 are spacedinwardly or toward the longitudinal axis X_(M)-X_(M).

FIGS. 3 and 6 are enlarged portions of a stent illustrating certainaspects of a stent design that can be optimized based on the desiredperformance of the stent. Each cell segment 140 is shown including: 1) afirst segment 141 that extends from a first connection location 130 a topeak 150; 2) a second segment 142 that extends from peak 150 to valley160; 3) a third segment 143 that extends from valley 160 to peak 152; 4)a fourth segment 144 that extends from peak 152 to valley 162; 5) afifth segment 145 that extends from valley 162 to peak 154; 6) a sixthsegment 146 that extends from peak 154 to valley 164; 7) a seventhsegment 147 that extends from valley 164 to peak 156; and 8) an eighthsegment 148 that extends from peak 156 to a second connection location130 b. Additionally, as shown in FIG. 6, peak 152 is part of connectionlocation 132. Collectively, peaks and valleys are referred to herein asnodes. As illustrated by the example stent shown in FIG. 3, for example,an example stent design may include a respective peak (such as peak 152)defined by a node that is directly adjacent to a respective valley (suchas valley 160) defined by another node moving circumferentially alongthe undulating pattern of a structural member for cell segment 140. Therespective peak (such as peak 152) that is defined by the node maydefine an apex of the respective structural member as a furthest pointof the respective structural member in a first direction (e.g., thedirection to the left along longitudinal axis A-A for the perspectiveshown in FIG. 3) between directly neighboring valleys (such as valleys160 and 162) along the undulating pattern of the structural member forcell segment 140. The respective valley (such as valley 160) that isdefined by the other node may define another apex of the respectivestructural member as a furthest point of the respective structuralmember in a second direction (e.g., the direction to the right alonglongitudinal axis A-A for the perspective shown in FIG. 3) betweendirectly neighboring peaks (such as peaks 150 and 152) along theundulating pattern of the structural member for cell segment 140.

In the illustrated embodiment, segments 141-148 extend generallylongitudinally along stent 100. The term “generally longitudinally” willbe understood to mean that segments 141-148 are closer to a parallelrelationship relative to the axis A-A of stent 100 (e.g., FIG. 3) thanto a transverse relationship relative to the axis A-A of stent 100.

Each node comprises a generally semi-circular arcuate segment includinga radius of curvature “R_(S)”, a length “L_(S)” (along axis A-A), and awidth “W_(S)” (perpendicular to axis A-A) (see FIG. 3). The radius ofcurvature “R_(S)” is defined as the distance of the circular arc whichbest approximates the curve at that point, and is measured along aninside edge of the node, as shown in FIG. 3. In disclosed embodiments,peak 150 and valley 160 may comprise a radius of curvature between about0.00300 inches and about 0.00400 inches (e.g., equal to about 0.00318inches). In disclosed embodiments, the valley 162, peak 152, peak 154,valley 164, and peak 156 may comprise a radius of curvature betweenabout 0.0001 inches and about 0.0010 inches (e.g., equal to about 0.0005inches). Moreover, it is envisioned that the radii of curvature of peak150 and valley 160 are equal or substantially equal to each other, andit is envisioned that the radii of curvature of each of valley 162, peak152, peak 154, valley 164, and peak 156 are equal or substantially equalto each other. It is further disclosed that any peak and any valley ofeach cell 120 can have any of the disclosed radii of curvature.

In one embodiment, a stent may have more than two distinct radii ofcurvature within each cell 120. By way of non-limiting example, it canbe envisioned that stent 100 includes cells 120 where a larger (orlargest) radius of curvature between adjacent nodes is between about200% and about 700% (e.g., approximately 250%) larger than the smaller(or smallest) radius of curvature between adjacent nodes.

The width of peak 150 and valley 160 may be between about 0.0250 inchesand about 0.0265 inches (e.g., equal to about 0.0258 inches). The widthof valley 162, peak 152, peak 154, valley 164 and peak 156 may bebetween about 0.0240 inches and about 0.0250 inches (e.g., equal toabout 0.0245 inches). It is further envisioned that any peak and anyvalley of each cell 120 can have any of the disclosed widths.

The length of peak 150 and valley 160 may be between about 0.0150 inchesand about 0.0170 inches (e.g., equal to about 0.0160 inches). The lengthof valley 162, peak 152, peak 154, valley 164 and peak 156 may bebetween about 0.0150 inches and about 0.0170 inches (e.g., equal toabout 0.0160 inches). It is further envisioned that any peak and anyvalley of each cell 120 may have any of the described lengths. The width“Wcp” of connecting portions 130 and 132 (see FIG. 5) may be betweenabout 0.0100 inches and about 0.0200 inches (e.g., equal to about 0.0149inches).

As discussed hereinabove, the stent 100 includes cells 120 havingmultiple nodes, wherein at least one node has a different radius fromthe other nodes. It is envisioned that these features help extend thelife and/or durability of the disclosed stent 100. For example, themechanical strains undergone by stent 100 when stent 100 is within apatient's vasculature (e.g., within a region subject to repeated jointflexure) results in a more balanced distribution of strains versus atypical stent where each node has the same radius, for example. Acombination of finite element analysis, durability testing, fatiguetesting, and repeating bending load testing may be performed to helpdetermine the ranges of dimensions for each node and to tune the desiredperformance of a given stent 100. For example, to help balance thestrains undergone by stent, the radius of the node that experiences thehighest strains during testing (e.g., finite element analysis,durability testing, fatigue testing, and/or repeating bending loadtesting) is increased. If/when a different node experiences the higheststrains during a subsequent test, the radius of that node is increased.This testing process is repeated until the strength and/or size of thecompacted diameter become unacceptable for its desired application,and/or until additional increases in node radius provides negligibleadditional improvement in strength or durability.

When stent 100 is compacted into the catheter (i.e., its predeployedconfiguration), the diameter of stent 100 is reduced as compared to whenstent 100 has not yet been loaded into the catheter (i.e., its preloadedconfiguration). This associated reduction in stent circumference isaccommodated by reduction in the angles between segments which resultsin an increase in bending strain (e.g., especially adjacent nodes). Asthe cell is deformed (e.g., when stent 100 is loaded into catheter, orwhen the delivery system is navigating through the vasculature to thetreatment site), especially during bending or axial loading, certainangles between adjacent segments increase or decrease more than othersdue to the lack of symmetry inherent in most flexible stent designs. Asa result, there is a greater amount of strain in the nodes that connectthose adjacent segments. The amount of strain concentrated near thenodes can be calculated using finite element analysis, for example.

The maximum strain in a deformed stent is called the peak strain. Thepeak strain typically occurs in a single segment in the vicinity of anode although it may occur elsewhere in the stent depending on the stentdesign. Predominant strains in stents may be tensile (usually defined aspositive) or compressive (usually defined as negative). Strains can becategorized as being of two kinds: normal strains and shear strains.Normal strains can be positive (e.g., tensile) or negative (e.g.,compressive). There are positive and negative shear strains as well, butin this case the sign convention is arbitrary, and physically there isno real difference between positive and negative shear strains. Normalstrains, which are also referred to as principal strains, are generallythe basis for strain analysis and durability analysis of stents.

High tensile strains may cause cracks to initiate and propagate throughthe stent, leading to reduced fatigue life and stent fracture (i.e.,failure mode). Compressive strains do not tend to cause cracks, and sogenerally do not cause reduced stent life unless the magnitude of thestrain is extraordinary. Some portions of a deformed stent may be highlystrained during use while other portions may not be strained at all. Adeformed stent can be thought of as a collection of tiny volumetricregions, each region having a strain level; collectively, the strainlevels of the regions range from a maximum negative value to a maximumpositive value. For a stent in service in the body, if stent strains aremaintained below the endurance limit of the stent material then highfatigue life may be expected assuming the stent material has undergoneproper materials processing and surface finishing. However, if a stentin service in the body suffers stent strains above the endurance limitof the stent material then high fatigue life cannot be expectedregardless of stent material processing and surface finishing.

Commonly, stents are designed such that the strain in the stent remainsat a low level under pulsatile loading conditions, i.e. underoscillating circumferential compressive strains. However, it has beendetermined that stents implanted in other locations, for example withina patient's vasculature at or near a patient's joint, can subject astent to larger amounts of strain than previously predicted.

Bending and any associated elongation of stent 100 results inconcentration of tensile strains at and within particular nodes therebyexposing the segments near or adjacent the nodes, and the nodesthemselves, to lower fatigue life. Concentration of compressive strainsin other nodes permit the segments near or adjacent those nodes tosustain higher fatigue life. As such, balancing the strains experiencedby the stent 100 increases the overall fatigue life of stent 100.Balancing the strain may involve changing the design of the stent 100such that the nodes that are otherwise exposed to higher levels oftensile strains have a way to distribute that strain to help improve thefatigue life of the particular node and adjacent segments, and thus,help improve the fatigue life of the entire stent 100.

The stent 100 of the present disclosure helps balance the strain byproviding nodes with different radii of curvature from one another. Asthe strain is concentrated in regions where the radius of curvature isthe smallest, it follows that by increasing the radius, the peak strainis reduced. The nodes of each cell that undergo the larger amount ofstrain have a larger radius associated therewith. Thus, nodes having thelarger radius of curvature have a lower amount of peak strain associatedtherewith, and which thus improves fatigue life (i.e., helps prevent thestent from breaking). Further, the particular nodes of stent 100 thatinclude a larger radius of curvature are the nodes that were found toundergo the highest peak strains during various testing procedures.Therefore, the overall life and performance of the stent is improved.

However, while altering the radii of various nodes may improve certainaspects of the stent design, such changing of radii may decrease thestrength of at least part of the stent. More particularly, stent 100 iscompacted to a relatively small diameter in order to enable stent 100 tofit into a delivery system that travels through a patient's vasculature.Generally, as the node radius increases and the segment widths remainconstant, the minimum compaction diameter increases in proportion to theincrease in radius. If the required compaction diameter is desired to bea fixed amount, then as the node radius is increased, the segment widthswould have to decrease. This decrease in segment width may lead to adecrease in stent strength. Thus, for each stent design and desiredapplication, it is possible to tune the overall stent design to ensurethe durability benefits outweigh the loss of strength or an increase incompaction diameter due to increasing the node radius. By way of anon-limiting example, for venous stents (as compared to arterial stents)the diameter of the delivery system may be less critical for tworeasons: 1) veins generally have larger diameters than arteries; and 2)blood pressure is lower in veins versus arteries, so the size of anaccess hole made to get the delivery device into a vein may be lesscritical, as once the procedure is complete, it is easier to stop thebleeding from a hole in a vein than in an artery. Thus, the design of astent can be tuned for a venous application by considering the desiredstrength of the stent, the desired durability, and the desired size ofits compacted diameter, along with the interplay between these criteria.

It is further envisioned that in addition to stent 100 having nodes withdifferent radii of curvature from one another, at least one node ofstent 100 includes a non-constant radius of curvature. In certainsituations, a stent having a combination of nodes with different radiiof curvature and with non-constant radii of curvature may furtheraugment the balanced distribution of forces. Further details of stentshaving nodes with a non-constant radius of curvature is disclosed inU.S. application Ser. No. 13/834,713, filed concurrently with thepresent application on Mar. 15, 2013 and published on Sep. 18, 2014 asU.S. Patent Application Publication No. 2014/0277379, the entirety ofwhich is hereby incorporated by reference herein.

It is envisioned that the each cell 120 and the entire stent 100 can beof any reasonable dimension for the intended purpose of use within apatient's vasculature. Likewise, the total number of cells 120 can be ofany reasonable value. Further, as shown in FIG. 4, connector members 180may be included on stent 100 to temporarily secure stent 100 to adelivery device, for example.

In disclosed embodiments, the inside diameter of a preloaded stent 100(i.e., prior to insertion into a catheter) is between about 0.5000inches and about 0.6000 inches, and the inside diameter of a predeployedstent 100 (i.e., compacted within a catheter) is between about 0.0500inches and about 0.0600 inches.

In use, stent 100 is advanced to a site in a bodily lumen. Stent 100 isthen expanded at the site. Stent 100 may be expanded through anyconventional means. For example, stent 100 may be placed on the balloontip of a catheter. Here, the balloon is expanded at the site to generateradial forces on the interior of stent 100. The radial forces urge stent100 to radially expand, e.g., without appreciable longitudinal expansionor contraction. Plastic deformation of the material of stent 100 (e.g.,stainless steel) results in stent 100 retaining the expanded shapefollowing subsequent deflation of the balloon. Alternatively, the stent100 may be formed of a super-elastic or shape memory material (e.g.,nitinol).

Numerous modifications are possible. For example stent 100 may be linedwith either an inner or outer sleeve (such as polyester fabric or ePTFE)to facilitate tissue growth. Also, at least a portion of stent 100 maybe coated with radiopaque coatings such as platinum, gold, tungsten ortantalum. In addition to materials previously discussed, stent 100 maybe formed of other materials, including, without limitation, MP35N,tantalum, platinum, gold, Elgiloy and Phynox.

While three cells 120 are shown in FIG. 4 circumferentially connectedalong the diameter of stent 100, a different number could be soconnected to vary the properties of stent 100 as a designer may elect.Likewise, while each column of cells 120 in FIG. 4 is shown as havingthree circumferentially connected cells 120, the number ofcircumferentially connected cells 120 could vary to adjust theproperties of stent 100.

When forming stent 100 from shape memory metal such as nitinol, stent100 can be laser cut from a nitinol tube. Thereafter, stent 100 can besubjected to a shape-setting process in which the cut tube is expandedon a mandrel and then heated. Multiple expansion and heating cycles canbe used to shape-set stent 100 to the final expanded diameter. It isenvisioned that the final expanded diameter is equal to the desireddeployed diameter of stent 100. During expansion, it is envisioned thatstent 100 is axially restrained such that the length of stent 100 doesnot change during expansion. It is further envisioned that the finishedstent 100 has an austenite finish temperature less than bodytemperature. Here, at body temperature, stent 100 will self-expand tothe desired deployed diameter due to the shape memory characteristic ofthe metal forming stent 100.

In use, stent 100 can be mounted on a delivery catheter. As isconventionally known in the art, stent 100 can be held in a compressedorientation on the delivery catheter by a retractable sheath. As is alsoknown in the art, the delivery catheter can be used to advance stent 100to a deployment location (e.g., a constricted region of a vessel). Atthe deployment site, the sheath is retracted thereby releasing stent100. Once released, stent 100 self-expands to the deployed diameter.While an envisioned use for the features disclosed in the accompanyingfigures relates to that of a self-expanding stent, the features alsohave benefits when used with non-self-expanding stents (e.g., balloonexpandable stents made of a material such as stainless steel).

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. It is not intended that the disclosure be limited to theembodiments shown in the accompanying figures, as it is intended thatthe disclosure be as broad in scope as the art will allow and that thespecification be read likewise. Therefore, the above description shouldnot be construed as limiting, but merely as exemplifications ofparticular embodiments. Those skilled in the art will envision othermodifications within the scope and spirit of the claims appended hereto.

The invention claimed is:
 1. A stent comprising: a stent body defining alength along a longitudinal axis of the stent body and comprising aplurality of cells, the plurality of cells including individual cellsrepeating about an entire length of the longitudinal axis of the stentbody and an entire circumference of the stent body, each cell comprisinga first structural member and a second structural member longitudinallyopposed to each other and each extending in an undulating pattern aboutthe longitudinal axis, and at least one connector interconnecting thefirst structural member and the second structural member, wherein eachof the first structural member and the second structural member of eachcell comprises a plurality of cell segments defining a plurality ofnodes therebetween, the plurality of nodes defining peaks alternatingwith valleys around the circumference of the stent body along theundulating pattern, wherein, for each of the first structural member andthe second structural member of each cell, an inner edge of a first nodeof the plurality of nodes defines a radius of curvature that isdifferent from a radius of curvature defined by an inner edge of asecond node of the plurality of nodes, wherein the first node defines arespective peak directed generally in a first direction relative to thelongitudinal axis of the stent body, wherein the second node defines arespective valley directed generally in a second direction relative tothe longitudinal axis that is substantially opposite the firstdirection, wherein the respective peak is directly adjacent to therespective valley defined by the second node moving circumferentiallyalong the undulating pattern of a respective structural member, whereinthe respective peak that is defined by the first node defines an apex ofthe respective structural member as a furthest point of the respectivestructural member in the first direction between directly neighboringvalleys along the undulating pattern, and wherein the respective valleythat is defined by the second node defines another apex of therespective structural member as a furthest point of the respectivestructural member in the second direction between directly neighboringpeaks along the undulating pattern, and wherein the radius of curvatureof the first node is between about 250% and about 700% larger than theradius of curvature of the second node.
 2. The stent of claim 1, whereinthe radius of curvature of the first node is between about 500% andabout 600% larger than the radius of curvature of the second node. 3.The stent of claim 1, wherein the radius of curvature of the first nodeis about 250% larger than the radius of curvature of the second node. 4.The stent of claim 1, wherein the radius of curvature of the first nodeis between about 0.0030 inches and about 0.0040 inches.
 5. The stent ofclaim 4, wherein the stent body includes a predeployed inside diameterof between about 0.0500 inches and about 0.0600 inches.
 6. The stent ofclaim 1, wherein, when the stent is deformed, a peak strain at the firstnode is greater than a peak strain at the second node.
 7. The stent ofclaim 1, wherein the stent body exhibits a predeployed inside diameterof between about 0.0500 inches and about 0.0600 inches.
 8. The stent ofclaim 1, wherein at least one of the radius of curvature of the firstnode or the radius of curvature of the second node is a non-constantradius of curvature.
 9. The stent of claim 1, wherein each cell of theplurality of cells defines an opening in the stent body.
 10. The stentof claim 1, wherein the plurality of nodes comprise a plurality ofgenerally semi-circular arcuate nodes.
 11. A method comprising:inserting a stent into a body lumen of a patient when the stent is in apredeployed configuration; and deploying the stent to an expandedconfiguration while in the body lumen, wherein the stent includes: astent body defining a length along a longitudinal axis of the stent bodyand comprising a plurality of cells, the plurality of cells includingindividual cells repeating about an entire length of the longitudinalaxis of the stent body and an entire circumference of the stent body,each cell comprising a first structural member and a second structuralmember longitudinally opposed to each other and each extending in anundulating pattern about the longitudinal axis, and at least oneconnector interconnecting the first structural member and the secondstructural member, wherein each of the first structural member and thesecond structural member of each cell comprises a plurality of cellsegments defining a plurality of nodes therebetween, the plurality ofnodes defining peaks alternating with valleys around the circumferenceof the stent body along the undulating pattern, wherein, for each of thefirst structural member and the second structural member of each cell,an inner edge of a first node of the plurality of nodes defines a radiusof curvature that is different from a radius of curvature defined by aninner edge of a second node of the plurality of nodes, wherein the firstnode defines a respective peak directed generally in a first directionrelative to the longitudinal axis of the stent body, wherein the secondnode defines a respective valley directed generally in a seconddirection relative to the longitudinal axis that is substantiallyopposite the first direction, wherein the respective peak is directlyadjacent to the respective valley defined by the second node movingcircumferentially along the undulating pattern of a respectivestructural member, wherein the respective peak that is defined by thefirst node defines an apex of the respective structural member as afurthest point of the respective structural member in the firstdirection between directly neighboring valleys along the undulatingpattern, and wherein the respective valley that is defined by the secondnode defines another apex of the respective structural member as afurthest point of the respective structural member in the seconddirection between directly neighboring peaks along the undulatingpattern, and wherein the radius of curvature of the first node isbetween about 250% and about 700% larger than the radius of curvature ofthe second node.
 12. The method of claim 11, wherein the radius ofcurvature of the first node is between about 500% and about 600% largerthan the radius of curvature of the second node.
 13. The method of claim11, wherein the radius of curvature of the first node is about 250%larger than the radius of curvature of the second node.
 14. The methodof claim 11, wherein the radius of curvature of the first node isbetween about 0.0030 inches and about 0.0040 inches.
 15. The method ofclaim 11, wherein, when the stent is deformed, a peak strain at thefirst node is greater than a peak strain at the second node.
 16. Themethod of claim 11, wherein the stent body exhibits a predeployed insidediameter of between about 0.0500 inches and about 0.0600 inches.
 17. Themethod of claim 11, wherein at least one of the radius of curvature ofthe first node or the radius of curvature of the second node is anon-constant radius of curvature.
 18. The method of claim 11, whereinthe body lumen of the patient comprises a blood vessel of the patient.